Eloqua AppCloud | How to show User Consent page only once?

Hi,

I've developed an Eloqua App Cloud app with a Menu Service in it. In the "Action URL" field of Menu Service, I've given the URL to call Eloqua OAuth2 API authorize endpoint.

https://login.eloqua.com/auth/oauth2/authorize?scope=full&redirect_uri=https%3A%2F%2Fqa.at-event.com%2Flogin&response_type=code&client_id=9a577f77-8ae6-4159-b6f6-7f98671a61c6&access_type=offline

which redirects user to the User Consent page asking for permission for the application to access Eloqua on User's behalf. When user clicks "Accept" , user is redirected to my web application URI.

Now, This might be a naive question, but I really can not figure it out how do I restrict my application to do this authorization and Consent only once? I mean, only when the user launches the app for the first time? How can I get the information whether a user has provided the consent and not to show this to him again? Will it help if I store the Authorization code returned by this service call? but I believe that this code expires quickly... Then, how can I get user's consent only once, and then get token each time to access eloqua resources without taking user's consent?

Thanks and any responses much appreciated.

Rubab,