Hello
Arrive needs to be followed by a prepositional phrase ( time phrase ) so it can be followed by :
IN - HE WILL ARRIVE IN THE MORNING OR HE WILL ARRIVE IN OCTOBER
ON - HE WILL ARRIVE ON WEDNESDAY
AT - HE WILL ARRIVE A T SIX O �CLOCK
It can also have time expression and NO preposition, as in HE WILL ARRIVE TOMORROW
It can also be followed by a prepositional phrase of place. In this case it can be followed by AT / IN. For example
AT - HE ARRIVED AT THE AIRPORT
IN -HE ARRIVED IN PARIS TWO HOURS AGO
Hope this helps
Sam