Does a woman's cervix open before or after LH surge?

I’m just curious when the cervix starts to open for conception. Does it open right when LH (luetinizing Hormone) spikes or when egg is being sucked in by the finger like projections at the end of the fallopian tube? I want to think it opens before the egg is released but I know that happens after LH surge. Dies anyone know? Enlighten me.