In Singapore, we always use the construction 'last time' to mean 'in the past', and that seems to work well enough most of the time. like if I say

'Last time, I used to take a bus to work everyday.'

or

'Last time we didn't know know about the strict rules with regard to this matter.'

But come to think of it, now that I have actually written it down, it seems odd to use 'last time' to mean in a time that has past, when I probably have a specific time frame in mind, and don't just mean a vague time in the past. So perhaps, i could say

'Last time Singapore don't have Caucasians'

But with increased usage, and Singaporean's vague idea that the meaning of last time means 'in the past', we find weird sentence constructions such as:

'Last time at Zouk'

to mean an occasion at zouk that happened some time ago, but which, if taken literally, would actually mean the final time at Zouk. So.. interesting huh?

oh by the way, refer to http://www.lowyimin.com/ for some linguistic abuse. =)