You become empowered by the element of your last cast elemental ability, gaining an empowerment buff:
Elemental Empowerment: Fire: Weapon combo finishers apply Burning for 100% fire damage on up to 3 targets and reset the cooldown of Fireball / Firebolt.
Elemental Empowerment: Ice: Weapon combo finishers deal bonus 70% ice damage, apply Frozen on up to 3 targets if they are Chilled, and reset the cooldown of Frostbolt.
Elemental Empowerment: Lightning: Weapon combo finishers deal {formula}% lightning damage, apply Volatile, arc to up to 3 nearby enemies, and reset the cooldown of Lightning Strike.