I love teaching children. Sometimes they’ll come out with something that is blindingly obvious that had never occurred to me before.
On one such occasion a child suddenly piped up in the middle of a French lesson: “It’s easy to remember which is which out of ‘le’ and ‘la’ coz lady starts with ‘la’ and ‘la’ is the one for ladies!”
I like that. I’m going to use it from now on, but I’m also going to add a bit of my own: Lemsip starts with ‘le’. ‘Le’ is for masculine things and Lemsip is for man-flu.
Problem solved.