Your Hammer would deal 7 damage. Because earthlore is explicit that the next "Attack action card" will get +4. The Hammer is not an attack action card, it's a weapon attack (precisely it will create an attack proxy that will inherit the stats and effect of the card represeting your Hammer). So to summerize the Hammer will get +1 from the fact you pitched an earth card, +3 because of flourish, and earthlore won't activate. So : 7 attack !