I was interested so I looked this up.
There is a concise paragraph on the subject in New Fowler's Modern English Usage (1996):
Accepted placings:
(e.g.)
who could certainly have afforded
was roundly criticized
he had inadvertently joined
>>>
But there are many reasons for altering the position of the adverb
(change of meaning, emphasis, rhythm, etc.):
e.g.
there is little chance that the student will function effectively after he returns to China.
<<<
RATHER THAN:
there is little chance that the student will effectively function after he returns to China.
