We had the same problem with our 70lb Keeshond - a little harder to hold and comfort. But that's what we did, because he would FREAK OUT (running, barking NON-STOP) whenever he heard a clap of thunder. The behaviour would continue until he hadn't heard any thunder for several minutes. Ironically he was pretty good until last summer (he was 3.5) and it used to be our Sharpei who would get upset, and she got a lot better last summer, she was 5.5. So, I don't have any advice other than try and calm him down as much as you can (we'd force Jager on the bed and try and cuddle him and pet him and make the shush noise quietly) and hopefully Odie will grow out it
Here's hoping you have light storm summer!
Tara