Since Ben isn't too active for these explanation, I will give a feble attempt...
I'm avoiding this thread until I know what happens in the day's stage. Too many spoilers or threat of spoilers.
The breaks go off as soon as the start flag drops. The first hour and last hour are by far the fastest of the day. The first hour is spent organizing the breakaway. The last hour is reeling it in and keeping another from forming.
The lesser teams will simply relay attack and form breaks. The directors check the time gaps and decide to let guys go or not. By the time the TV coverage begins, the fireworks are over and things have settled down. The directors have said, "Ok, none of these guys are a threat. Let them go!"
Before the stage begins, riders are talking to each other and forming alliances. They share their breakaway plans in hope of getting help from companions in a break or teams in the peloton. Directors have sheets of race numbers of riders that they will not let get away at all. The break that survives often consists of random domestiques on relatively quiet teams hoping to score air time for their sponsors.
The gaps that the break is allowed is often based on the placing of the highest rider in the break. If he is ten minutes down on GC, the team of the yellow jersey will decide that it is ok for him to get 8 minutes (or some other number) up the road. Any more than that and they will go to the front of the field to limit the gap.
The team of the yellow jersey is often responsible for keeping the break in check. At some point, the teams with sprint ambitions will come to the front and help. They want the stage win. At that point the yellow jersey team can sit up and just stay out of trouble.
This will change as we get to the mountains. The sprinter's teams disappear and are replaced by the teams with climbers.
After watching tours for decades, I love the intricate battles that go on inside the peloton. Beside the common jersey competitions, there is a team competition, most aggressive rider, and honor that influences the strategy. Teams often get pissy with each other and you see interesting things develop. There is often much much more going on than you see or hear commented on. Lots of fun when you understand it all. When one competition appears decided, there are still many reasons to keep watching.
Vohkler is a French pride and joy. Because he is in yellow, the crowds come alive. He gained yellow in 2002 (?) after a long breakaway. He held it for ten days and turned himself inside out to hold on to it. That is why he is so popular with the press. Thor did similar things this year but Vohkler was even more impressive.
FWIW, I am a huge Chris Horner fan. Really disappointed to see him out. His post-race interviews are hilarious and insightful. I miss him already. I suspect he will one day take over for Bobke as the retired clown of the media.