i just owned that guy with no problem with my ele by using the one elemental that is mostly overlooked....water
maelstrom owns them they never move out of its area. equip as many spells as possible and just keep smacking him while maelstrom interrupts all of his spells
Fire is even easier, all you have to do is avoid getting knocked down by the meteor shower and return the favor to the clone. Its pretty much game over at that point. Doing it as a earth or air elementalist would be more challenging, but not overly difficult.