Just to go back to the OP, and some of the replies - I'm a little confused by the way some of these terms seem to be used interchangeably. To my understanding, cyclic existence=samsara, and is not the exactly the same as dependent arising even though it arises dependently.
If we were to look at impermanent phenomena, which of course arise dependently, we would find:
1. some that have no beginning and no end (from Mahayana pov: eg mind streams/mental continuums)
2. some that have a beginning and an end (our physical bodies sure fit this one)
3. have no beginning but an end (eg samsaric cyclic existence, ignorance etc)
4. have a beginning but no end (eg liberation, Buddhahood, death)
referring back to a portion of the quote:
but still I say, there is no making an end of
suffering for those beings roaming and wandering on hindered by ignorance and fettered by
Samyutta Nikaya 22.99
Back to the discussion about time - which basically is just a measuring system for change, or if we wanted to be a bit more to the point - a mental construct that isapplied to intervals. Change/impermanence doesn't stop, so time continues to be somewhat relevant. When we start trying to find a beginning or end to time itself as that which determines the cause/effect, existence/non-existence of phenomena it starts to get a little silly.