Karen, I have made many pair of fingerless gloves and was taught to cast on in the middle of a row as follows:
At the point that you need to cast on, insert the RH needle between the top two stitches on the LH needle. Loop your yarn around and pull through as to knit, then place that loop you now have on the RH needle onto the LH needle. There is your cast on.
With the fingerless gloves there is always a little closing up of holes to be done in the finishing.
I hope that helps you.
Just wanted to say thanks for answering this question as I was about to post something similar!