Default send email address not working

I am trying to have all my email sent automatically from my new email (lora@) address. However, it keeps sending from my old one (lake_trail@). I am able to receive both my old and new in the same folder and have changed my new email to default in outlook account settings, though it's just not automatically sending it as my new one when I reply to emails originally sent to my old email address- I have to do this manually. 

I also have my "sent" emails when I use my new email address sent to an entirely different email folder (another email for my part-time University job).  Arg! I suspect it has something to do with the settings (new is POP/IMAP, old and university address are Exchange). I appreciate any ideas on what I can I do to clean this up!