ive taken clones 4 weeks into bloom with decent success in the past.when you take the clone you will have to take a cutting with a small bud on it.your clone will start growing out of the bud after it roots.leaves will look weird at first, but will straiten out in time,with a lot of side branching
Technically, you can take clones at any time, however, the further you are into flowering, the harder it is to get them to root and they will take longer to root. What happens is that they start producing a flowering hormone and you have to reverse that with longer light periods, which can take a couple of weeks. This has to happen before the plant will start growing roots. So basically the further in you are, the less chance of a successful clone.