I think it might be sense 3 of this Daijirin definition, which defines it as
…するときはいつも…する, which I think can be defined as "whenever (you) do ..., (you) do ...":
Whenever I was working part-time, I was solely buying records, so I was working thinking that if I work for a day and a half, I can buy an LP.
For example, from Daijisen:
When I was young, whenever I saw a train I was delighted.
I think this is distinct from another similar usage of
～ては (sense 4 at Daijirin), which is defined as two actions etc which make a pair and are repeated, for example:
(I) alternate between falling down and getting up, falling down and getting up...
Edit: Reverted the definition to an earlier version based on suggestions in the comments.