Wow that was a bit of a battle. Tried to do it in the least tools possible!
It's been a while since I've solved a weekly challenge. I may not have been as fast as @kat but I'm glad that I took the time to look at this problem. @kelly_gilbert and I have a very similar solution (spoiler). This was fun
This one had RegEx written all over it, at least for me. Ran into some issues trying to chain things together so I broke it up into individual words then split the processing whether the word started with a vowel or not.