Pickle resolved - the orange cake is now moist
Thanks to all the cooks who came forward with advice! In the end, I added an additional egg, a little more orange juice, and reduced the baking time by 10 minutes. Plus instead of a glaze, I drizzled the still-warm cake with a simple citrus-y syrup. Success!!
Thank you all for your suggestions! The Foodpickle and the picklers ROCK!