punctuation - Use of a semicolon before and comma after "however"

Several years ago, a previous boss told me to use a semicolon and comma with the word "however". I've always questioned this and would like to know if the following random sentences are using the correct method.

1. Our plane was delayed overnight; however, the airlines reimbursed us for lodging.


2. It looks as though he's upset; however, she told me he always has that look on his face.



3. I want to find him a nice gift; however, I am a broke until payday.

Normally I would use a less "wordy" sentence in casual writing, but hopefully the example will suffice. For example, on number 3 I would usually type:

I want to get him a nice gift, but I'm broke until payday.