Archiving and Restore - Effect on DB

I archive out all data after 7 days. This gets written to .csv file locally. When I wish to report on a period longer than the last 7 days I have to restore archives (which is a pain hence my request for a data warehouse for archiving).

My question though is how does this affect the DB? Are the following true:

When the daily arching task runs at 02:00, is all data older than 7 days removed from the DB and placed in .csv files?

If so, when i do a restore and this data is added back into the DB, how long does it live there? Is is archived again on the next archive run a 02:00 ?