User blog comment:Woverine294/How did Thor lose his power to mjolnir and Female Thor claimed it/@comment-26423909-20150607155839/@comment-16461120-20150608000145

My head tells me it is something that took place somewhere during Simonson's run (Thor Vol 1 337 to Thor Vol 1 382), but my heart wants it to be related to the fact that Odinson basically abandoned his feelings for Jane way back in Thor Vol 1 136.