You should allow the "god of thunder" as a valid translation. Even though "fulger" translates into "lightning", in English, the god is referred to as the "god of thunder" more than the "god of lightning".
In a christian vision mixed with old romanian stories this sentence may be: "Ce sfânt patronează furtunile?" and the answer may be "Sfântul Ilie". For romanians, the word "zei" is used for the english word "gods" especially with the refference to the greec mithology.