My ranger has a bow I used the 'opal of the ild rune' on. It gives my bow an extra 1d6 fire damage.
The lightning arrow spell states that it replaces the normal damage of the weapon (the arrow in this case). But, the fire damage is added by the bow, not the arrow.
So, does the fire damage stay, because it is part of the bow, not the arrow? Or does the lightning arrow replace all damage, including the extra damage from the bow?