Like a non-sequitur, a pre-sequitur doesn't follow what immediately preceded it, but instead relates to something that came earlier, but too long ago to be relevant. It is a sudden or jarring break in the chronology, but it does follow... when you remember what it refers to. Often used as a comic device.
A classic pre-sequitur:
during Mary's job interview
Lou Grant: What religion are you?
Mary Richards: Mr. Grant, I don't quite know how to say this, but you're not allowed to ask that when someone's applying for a job. It's against the law.
Lou Grant: Wanna call a cop?
Mary Richards: No.
Lou Grant: Good. Would you think I was violating your civil rights if I asked if you're married?
Mary Richards: Presbyterian.