According to the top answer from [Word order with “so” and “also”](https://german.stackexchange.com/questions/8206/word-order-with-so-and-also), "so" is never used at the start of a sentence as an interjection.

That said, in Pokemon Schwarze Edition, this is said at some point:

> 
> So, dein Pokemon ist wieder putzmunter!
> 
> 
> 

AFAIU, "so" should have been "also", with the sentence meaning "Well, your pokemon are lively again!". Is this correct?