Lorna was invented by the English author R.D. Lorna Doone (1869) — R.D. Blackmore's romance set in 17th-century Exmoor; the title character is a noblewoman raised by the outlaw Doone clan who falls in love with the yeoman farmer John Ridd; one of the best-selling English novels of the Victorian era and never out of print since publication, adapted for film and TV more than a dozen times. The Lorna Doone shortbread cookie (Nabisco, 1912) was named after the novel and remains one of the longest-running packaged cookies in America.
Lorna does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Lorna reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.