The lumps could be fatty lumps that often develop with age. The vet can take a needle biopsy to test if they are fatty and if you are worried I'd suggest getting that done.
Have you had a scraping done of the skin flakes to make sure it isn't a bacterial infection that needs antibiotics?
He may have a food allergy so I'd suggest an elimination diet. Food allergies often develop as a dog gets older. My boy is sensitive to chicken and turkey and they are in lots of commercial products and it's a fairly common allergy. You need to find a protein source that he hasn't had before and then keep him on that diet for 3 months and see if it has improved. If you give commercial food that is easily done - there are many vet diets you could try and some shop ones. I used Wellness Simple salmon and potato and I also cooked fish and potato meals.
Do you bathe him? My 10 year old male has had skin problems for the last 2 years that I'm having trouble pinning down. But I do know it's so much better after I give him a bath with special sensitive skin formula. I have Plush Puppy sensitive skin and recently started using one I got from the vet, which has been great. If the skin flakes are localised you can rub in some baby oil or sensitive skin conditioner.
If it's really bad, adding something to the diet may help a little, but if it's really bad, unless he has a deficiency, it's unlikely to cure it.
There was a recent thread by another member on dry flaky skin - have a look in the health section.