I like the theory Kettledrum, but L is not an accepted abbreviation for lady! I wonder if they meant if you say 'elle' (as in 'she') it sounds like L then, as you say, reverse TO. But no indication of French so maybe not...!
Quizmonkey - You are, of course, right in theory ...... but ...... some compilers don't seem to think your rigorous approach is necessary and use the first letter of almost any word as an abbreviation.
encee hasn't given us the source of the clue.