As usual, correct me if I'm wrong experts; here goes:
Static Rollover - helicopter has rolled to such an angle that a line straight down from the CG is outside the skids / wheels, and it falls over.
Dynamic Rollover - helicopter is picking up to the hover. Either from lateral cyclic input, or a skid getting caught on something, a roll develops. Once a certain angle of roll is exceeded, even full opposite cyclic can't tilt the lift vector back past the vertical, so any lift from the rotor is pro-roll. The only option available is to dump the collective and hope that the static rollover angle hasn't been exceeded.
Sound reasonable?