It's likely to go dormant over winter, but not die all the way. Around here (southeastern Pennsylvania), it goes back to 4-6 inches over winter. Red clover is extremely variable as to when it goes to seed, even in my own yard, but definitely more over the entire range of where it can grow, so there isn't really a 'time' when it will go to seed. But it should be next spring, not this fall.
For me, it usually ends up being in late April to late May, depending on the winter. Plow it under when the first flowers fade. Any later and they'll form seeds. The higher the nitrogen content in your soil, the longer the plant will put off flowering, and put it's energy into getting bigger. It can get up over waist height before flowering, in good conditions.
Make sure you don't seed too thickly, because rye is a very aggressive early spring grower, and will outpace the clover for a while. Make sure there is plenty of space for the clover to fill in. The clover can fill in sideways lots more than rye can.