Hearthpwn

Alrighty then! Now that we've seen the whole set I have a better idea of what's available and what to include.

The earliest 'Played an Elemental Last Turn' effects are on turn 4, thus it's not particularly critical to have an elemental to play before turn 3 which is why I have 3 Elementals in the 3-Mana slot. 

Ideally your early curve in the vast majority of match-ups will be:

Mana Wyrm > Pyros/Sorcerer's Apprentice > Tar Creeper > Steam Surger/Water Elemental > Servant of Kalimos

Frostbolt and Fireball act as removal or burn depending on what you need, Flamestrike in case you're being swarmed. Primordial Glyph allows you to fish for an answer or grab something in advance for a future turn.

Frost Lich Jaina and Sindragosa add late game power plays that Elemental Mage has lacked up to this point in case playing the tempo game hasn't won you the game yet.

Arfus has a good chance to add a card that could generate a huge tempo swing and is low enough cost to be worth it. The Lich King is also such a huge threat in the late game if you have a neutral or dominant board. 

I cut Arcane Intellect for The Lich King because I was finding that with so much card generation running out of steam was very rarely an issue thus an extra late game threat outweighed the card draw.