Hi
I am kind of in the same dilemma:
In my case
First arrival: Student (1year 1 month)
July 2009-Aug 2010
Second arrival: Student; temporary skilled (4years 2 months)
Feb 2011-April 2015(visa ended)
(11 months 27days gap between the second and third visit)
Third arrival: PR
April 2016-
I am not sure
a) if i am eligible to apply for citizenship this April 2017
b) What is my lawful residence date
c) if my 4 years reset what date do i consider for the reset date.
If someone could shed a light through your experience that would be much appreciate.