Yes. Since you called the horn an attack (we all thought it was an ability or, at the very least, a spell), questions came up. Does it miss? Does it crit? Do Orvald's shield, Zhenodel's, and Zedil's necklace effects count as attacks then? It's just that for attacks, if they always hit, it's usually stated so.
Not Orvald's shield, but Ferlyuts's.

