Please refer to :
http://www.flyertalk.com/forum/catha...unge-faqs.html
Please scroll down until you see :
Am I entitled to use The Arrival?
You are only entitled to use the above lounge as the others mentioned are for departing passengers.
You need to pass immigration and customs before going to The Arrival.
Which hotel are you staying? You may request early check in at noon. Most hotels would assist when possible.