The only connection between the name Eliahu and the name Alexander are the leters Alef-Lamed
or in Hebrew אליהו and אלכסנדר
But ,what I don’t understand is that the name Elijahu and the name Alexander are Holly names,
“Shem Kodesh” שם קודש. It was usual to change a Holly name to a secular name that use the same first later
a sample: Abraham was changed to Albert, Moshe to Moris, Gershon to Gerhard and more.
Alexander sometimes was change to Sander,Sender, Axelrod,Zand, Zender and more names.
but this names are nor realy a chang of the name, the only shorted the origin name Alexander.