To stop it from opening with Blank at start up.
Start up normally (yes you'll get blank page, but changes you make will stop it from then on).
Now at File menu click and choose open from Template.
When template menu opens click to remove Check mark, the check box in bottom corner.
Don't show this when starting up.
Now the template menu will open and a Blank document will not appear.
As for closing document when switch to another application. Try the following:
Hold down Command Key(⌘) then tap and hold Tab key then choose word and release.
Actually this is required by Apple's User Interface Guidelines for application to open a Blank page regardless of the application. (Utilities are no considered applications).