When you add an Enchant to your weapon /see Enchants in the Dragon Disciplines skill tree/ your arrows also become enchanted - Exploding Arrow for Fire Enchant, Freezing Arrow for Cold Enchant, Lightning Strike Arrow for Lightning Enchant - a lightning strikes from the skies, and Poison Cloud Arrow for Poison Enchant - a small poison cloud appears over the enemy. This adds more arrow variations. Enchants and Arrow skills should use some mutual bonuses.