If you cast Seize the Storm with no instant or sorcery cards in your graveyard and no cards with flashback in exile, the Elemental will start as a 0/0 creature. However, state-based actions won't be checked until after Seize the Storm has finished resolving. The Elemental will then be a 1/1 creature and survive because Seize the Storm will either be in your graveyard or in exile.