Eloise

The medieval English form Helewis or Helwise is the origin of the surnames Elwes and Elvis, and so is almost surely also the ultimate origin of the male given name Elvis.

I am sorry, but "Saint Eloise" as you call her, is not seen as a saint, and her name is spelled with a h, making it Héloïse. I should know, I'm called Héloïse (I'm French and often have made research on this name). Héloïse can also mean glorious fighter (Germanic) or god (in Hebraic).

Actually, Eloise is derived from Louis/Louisa, meaning "Famous Warrior." It's a beautiful and elegant name, really, and pleasantly uncommon.