With Rogue, it was a case of (after absorbing the entirety of Thor's life force and thus essentially becoming Thor) in What If? Vol. 2, #66. (Oct. 1994), according to the Wiki regarding Mjolnir.
Yeah, then she drops it to fight "fair" when facing Storm.... and loses.
Reminds me of a time in one of the comics where Storm fought Thor. they zap at each other with lightning for a while, then Thor decides on a different approach. He kisses her and sucks the air out of her lungs. Then she passes out from anoxia. Amusing battle.