Suppose I am an abjuration wizard with 3 temporary hit points and 5 hit points on my Arcane Ward. If I take damage, which hit points absorb damage first? For example, what will be my status after taking 4 damage? Will this damage force me to make a saving throw to maintain concentration? (In case it matters, assume that I have 30 hit points.)
As written, it seems that both effects trigger simultaneously (emphasis added):
Whenever you take damage, the ward takes the damage instead.
Temporary hit points:
When you have temporary hit points and take damage, the temporary hit points are lost first, and any leftover damage carries over to your normal hit points.