Question about punctuation

Question

In the first sentence, Bonjour is part of the sentence.   In the second sentence, we have Bienvenue as a stand alone and not part of "Nous avons..."  If the person had replied Bonjour instead of Bienvenu, would Bonjour be included in the second sentence, i.e. Bonjour, nous avons... ?  Similarly, the last sentence includes bonne visite.  How does one know when to include these sort of expressions in the sentence or to have them stand alone ?

Accepted Answer

Hi Frank, 
Now, I am not the best punctuator and we have been accused of using too many exclamation marks in the past.
Stand alone expressions like -
Bon voyage !
Bonne route !
Bienvenue !
etc
would have an exclamation mark. 
The 'bienvenue' as part of the sentence you mention could be either followed by a comma or an exclamation mark depending on the mood you are trying to create.
Please take a look at the following page I found which is pretty good in my humble opinion -
https://www.lingoda.com/blog/en/when-use-exclamation-mark/#:~:text=Opening%20with%20a%20greeting,person%20you're%20writing%20to.
Bonne Continuation !