Do not close that command prompt or Armory will not work. It is a prompt for a background process that Armory runs and it must stay open for that to work. Do not close it, Armory should close it for you when you stop the wallet.
I just downgraded from Bitcoin Core version v0.15.0.1 (64-bit) to Bitcoin Core version v0.15.0 (64-bit) to fix the "offline node" issue.
With 15.0.1 the command prompt was not closing on its own. After I downgraded to 15.0 the command prompt has started closing on its own.
Thank you so much for your help.