Oy I was going to save this for something else and type up a proper lore, but I kinda need Telly to rank up in the immediate future so I can quadcast with him >w<
Yes, his element is Earth. I have a happy mini TedTalk about why electricity is totally an Earth-based element and I'll go dig it up from wherever I stuck it.
In the meantime, look it's the lightning pole~@! Please refrain from getting close to him in this state. He has the staff for a reason. And he's doing the sparky sparky things for a reason.