Elsie is the Scottish diminutive of Elizabeth — from the Hebrew Elisheba ("my God is my oath"). Lady Mendl (married Sir Charles Mendl in 1926); her Versailles villa was the setting for Salvador Dalí, Cole Porter, and the Duke and Duchess of Windsor. Morgan Jr. residence. Elsie Roberts — American chef.
Elsie 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 Elsie reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.