Phil Lawler has found a relevant document from the Pontifical Council for Legislative Texts that says it’s the responsibility of the priest to determine who should receive the Eucharist. In other words, he doesn’t have to wait for a bishop to tell him otherwise.
The discernment of cases in which the faithful who find themselves in the described condition are to be excluded from Eucharistic Communion is the responsibility of the Priest who is responsible for the community. They are to give precise instructions to the deacon or to any extraordinary minister regarding the mode of acting in concrete situations.
4. Bearing in mind the nature of the above-cited norm (cfr. n. 1), no ecclesiastical authority may dispense the minister of Holy Communion from this obligation in any case, nor may he emanate directives that contradict it.