Can you explain the rules for the mwen to m' contraction?

"MWEN" can be used as personal pronoun: I or ME
"MWEN" can be replaced with contraction "m".
example:
1. Mwen te wè li.
    or 
   M te wè li.
   I saw it.

2. Rele mwen lè w rive.
    or
    Rele m lè w rive.
    Call me when you arrive.

"MWEN" can be used as possessives: MY, MINE (singular or plural)
example
3. pitit mwen - my child
4. pitit mwen yo - my children
Do not use contraction after a word that end with a consonant.
The word "pitit" ends with "t" which is a consonant.  So you cannot say "pitit m".  You will always say "pitit mwen".

5. pye mwen or pye m - my foot
The word "pye" ends with a vowel "e" which is a vowel, so you can say "pye mwen" or "pye m"

6. kesyon mwen or kesyon m - my question
The word "kesyon" ends with a nasal vowel "on", so you can say "kesyon mwen" or "kesyon m"

Sometimes a definite article may come after MWEN:
7. kesyon mwen an or kesyon m nan. - my question
8. kesyon mwen yo or kesyon m yo - my questions

We do not use contractions after these prepositions POU, NAN, SOU at the end of a sentence:

9. Malèt la tonbe sou mwen.
   You cannot say
   Malèt la tonbe sou m.

10. Fè sa pou mwen tanpri.
      you cannot say
     Fè sa pou m tanpri

11. Lespri Bondye te desann sou mwen
     you cannot say
     Lespri Bondye te desann sou m.


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