Thanks for the tip, Arnie (a.k.a. Mr. Barky) slept through the night for the past two nights, hurray 
I think the t-shirt idea really helped, he just gave a short yip and that was it, he didn’t even wake up for the thunder last night!! He’s such a gentle little dog and is becoming more cuddly and affectionate every day. He’s also starting to come back when called (on the long leash) which is a good sign. He’s off to get neutered tomorrow, maybe then he’ll stop longing for a girlfriend and making romantic advances towards his pillow, ahem.