A million times prettier than Dido in my opinion, and very rare. In fact, the only time I've heard it used was in "The Phantom of the Opera", when it's the name of the lead female role of the opera-within-the-musical "Hannibal". It's Elissa (played by Christine) who sings "Think of Me" at the begining of the show.
Elissa Landi (born Elisabeth Marie Christine Kühnelt) was an Italian-born actress who appeared in Hollywood films in the 1920s and '30s (e.g., The Sign of the Cross, After the Thin Man).