Colin,
I will do my best to be thorough and I hope it makes sense. I will start by saying that I'm sure "Louisa" was an early transcription error by someone who couldn't read Lorina. Family Search has a transcribed record for a Lorina Norman who was baptized on Feb. 21, 1738 in Westhall, Suffolk to a Thomas Norman and his wife Lorina.
On the Larter Family website, there are transcriptions of Suffolk Baptism's. There are four children listed as being the children of John and Lorina Larter. They were all baptized in Walberswick and they were:
John Larter, who was baptized Nov. 13, 1768
Edward Larter, who was baptized Jan 20, 1771
Lorina Larter, who was baptized May 28, 1772 and was buried June 10, 1772
Robert Larter, who was baptized Oct 22, 1775
This same transcription site has a Sarah Larter, baptized on Oct. 25, 1767 to Edward and Sarah Larter but there is a burial record for the infant Sarah Larter on Nov. 22, 1767 which is attributed to John and Lorina Larter, so I'm unsure of her parentage.
**The family moved to Witton, near North Walsham but I don't know when because I have not found a settlement certificate for them.
**On Dec. 24th 1793 at Bacton, Norfolk, Edward Larter of Witton married Frances Howlett of Bacton. I have 12 children listed for them, all baptized in either Witton or Bacton, one who was named after her grandmother Lorina born 1795, she married an Aaron Sewell. Another named Richard Larter born 1802, who is buried in the churchyard beside his grandparents (John and Lorina).
**Robert Larter born 1775 married Ann Cornish on Feb. 26, 1802 at Knapton, Norfolk. His parish was listed as Bacton and hers as Knapton. They had five children, all either baptized in Witton or neighboring Swafield. One of these children was named Lorina after her grandmother. This Lorina married Thomas Spice and is buried in the North Walsham Churchyard next to her mother Ann Cornish. Robert Larter died between 1811 and 1813. I have been unable to find the record but his "widow" married Richard Pilgrim in North Walsham on May 2, 1813 and his last child was baptized in 1811 Swafield.
Now to get to John and Lorina. These records are transcribed from the Witton Parish Register. Lorina Larter, was buried St. Margaret on September 24, 1811 age 73. On the same page is listed (in error) Edward Larter, who was buried January 17, 1812. In the Monumental Inscriptions of St. Margaret, Witton the listings are as follows: To the Memory of John Larter, who died January 31st 1812, aged 77 years. Also of Lorina, his wife, 1811, aged 76 years this September 20th. Prospect by the Father in who's service they were for many years, Distinguished for their honesty and fidelity.
**Next to them is Richard Larter son of Edward and Frances (Howlett) Larter. In Memory of Richard Larter, who died Sept. 8, 1856 aged 53 years. Also of Mary Ann, his wife, who died Jan 2, 1875 aged 72 years. Blessed are the dead which die in the Lord.
**Here are the burial records I have found for Edward Larter and Frances Howlett.
Frances Larter aged 61 of the Parish of Witton in the County of Norfolk was buried in the Protestant Dissenters burying ground in Bacton in the County of Norfolk on the 11th day of April 1828. This is probably the Bacton Baptist Chapel, which was founded in 1822 and is located between Bacton and Happisburgh.
***On October 15, 1829 in Happisburgh, Edward Larter of Witton, widower married Mrs Mary Durrant of Happisburgh. This is a little over a year after the death of Frances Howlett.
***Edward Larter was buried on Dec. 6, 1831 at age 60. His burial record is listed in Happisburgh (next to Bacton). It just say's burials of Happisburgh and does not list a churchyard.
On another note, at least three of Edward and Frances (Howlett) Larter's children married in Happisburgh between 1828 and 1834. This puts Edward in the area. His daughter Mary, married George Burton in 1828. His daughter Lydia married John Knowles in 1830 and his son Robert married Mary Clipperton in 1834.
Hope that's a little more helpful :-)