What is "established" on an RNAV approach?
NOTE: This answer is specific to the United States as the question uses an example approach procedure from an airport in the United States. Procedures may vary for other nations. Consult the respective Aeronautical Information Publication for specific guidance.

As long as you hear the magic words "cleared  approach," you can begin your descent as soon as you cross the IAF the first time (while beginning your teardrop maneuver) and continue to descend to the minimum altitude while in the circuit, which is at or above 2000 for this particular procedure. 

Note that you MUST be on a published segment of the approach before making your descent, otherwise terrain clearance is not assured. 

The controller will expect you to proceed from the IF to the FAF after the first circuit is complete (a course reversal maneuver, if executed counts as the first circuit). You must advise the controller if additional circuits are required in order to lose altitude. Also, if the controller clears you for a "straight-in" approach and doing so would result in an excessive descent rate, it is incumbent upon you as the pilot to advise the controller that you are unable.

Reference: FAA JO 7110-615, Approach Clearance