I work from home also. I hate to be the devils advocate here, but your dog may be barking its head off out of boredom after you leave. I never thought my dogs did this, until my neighbor mentioned she always knew when the pups were "home alone" because of the barking. We live in a subdivision, and the houses are close together. Once she said they sounded so frantic she thought someone might be sneaking in the back door, so she grabbed a bucket and looked over the privacy fence to make sure!!!
I was horrified, but she said they could only hear it when they were outside, and it was no big deal. She also said it only started after I started being home full-time. The little boogers get so used to someone being there to cater to their every whim!