(I just clarified my question (below) then went in and thrashed around in iTunes again - and found that the answer to my question was turning off 'Limit Episodes' in the 'Settings' option on the lower right of iTunes. Since I went to all the trouble to type in all this stuff below, I'll leave it there in case it helps some other rube someday.)
Thank you. Reasonable assumption, but the reality is I couldn't find any applicable area to post my question among the small handful offered - so I just picked what seemed closest - and perhaps chose poorly. Situation is simple - I have a Dell windows 10 PC with iTunes only (I don't really even know what Apple music is), and all I've ever done with it is subscribe to podcasts to sync with an ipod. Not an Apple guy, I used to find iTunes (just barely) user friendly, but after myriads of updates (currently at 12.13.4.4) it's kind of left me in the dust. The mystery I would like to solve is how to control exactly which podcasts of the many I've downloaded over the years show up from within the iTunes app. For example, if I have 100 radiolab episodes in the /iTunes Media/Podcasts/Radiolab folder on my PC - then under the iTunes Library under /Podcasts/Radiolab I would expect to see all of the 'cloud' podcasts which I have not yet downloaded PLUS those 100 Radiolab episodes. But I only see a few. Simply, I'd really like to crack the code on how iTunes decides which of the many podcasts in my PC library that it'll let me choose from when I'm in iTunes.