The church is resurrected when Jesus returns (1 Cor. 15:51-52; 1 Thes. 4:16-17).
The church was indeed resurrected at that time, and I'll tell you why I believe that.
First of all, I understand that there is no historical record of a one-time resurrection event that saw all the people step out of their graves, beyond the few around Jerusalem who were resurrected at Jesus' death. I think we both agree that the resurrection applies to all believers, not just those few people, so that can not have been the event. For that reason, it must be either (1) still future, or (2) misunderstood. It must be one of those two, and I'm going with option two, for the following reasons.
1. Jesus said all these things would happen before that generation passed away. (Matthew 24:34)
2. Jesus said some standing there would not die before all these things happened. (Mark 9:1)
3. Jesus said whoever obeys his word will never see death. (John 8:51)
4. Jesus said whoever believes in him will never die. (John 11:26)
5. Paul said we have already been brought from death to life. (Romans 6:13)
6. The temple was referred to as "heaven and earth" and was destroyed by fire, which means Revelation has been fulfilled.
7. Modern NDE experiences tell me that people no longer experience the state of death.
8. New testament authors do not describe people experiencing death, as the old testament does.
The way I understand the resurrection, is that it happens on an individual case by case basis as each person "dies", for the following reason: Jesus told us that if we believe in him, we will never truly die, meaning we will never experience the state of death the way the old testament saints did, because we will immediately, in the twinkling of an eye, be moved from this life into the next.
Jesus tried to explain this to his disciples several times:
John 11:26
and whoever lives by believing in me will never die. Do you believe this?”
John 8:51
Very truly I tell you, whoever obeys my word will never see death
Think about it. If we can never experience death, as Jesus said, then we can not be resurrected from death. It's logically impossible. Therefore it must have already happened. Therefore, we must reconsider what the resurrection actually looks like. If our preconceived notions don't fit the facts (which I listed above), then we have to change our preconceived notions.