Did the divorce occur once or twice, knowing that the first divorce was conditional with the intention of it taking effect upon the fulfillment of the condition, and then I followed it with the explicit phrase "you are divorced" to confirm the occurrence of the first divorce, and not with the intention of initiating a new divorce?

If you made your wife's divorce conditional on a certain event, and you intended for the divorce to take effect when that condition is met, then the divorce has occurred upon the fulfillment of the condition. If you then say to your wife, "You are divorced," intending to inform her of the previous divorce and to confirm it, then a second divorce does not occur with this utterance. However, if you intended to initiate a new divorce because you thought the previous one had not occurred, then in this case, you have divorced your wife twice. If these are the only two divorces you have pronounced on her, then you may take her back during her 'iddah (waiting period).