I grew up near a village named Ellerker, so won't help, sorry!

It also sounds a bit like Elektra, as in comic books.

Ellisa sounds similar to Elleka, but the "S" sound is softer than the "K". And you could go with a "Ka" sounding middle name (Kathryn, Karen, Carla, Carol...) so call her Ellie-Ka as a nickname.