Proper structuring of Lucene.Net usage in an ASP.NET MVC site

I'm building an ASP.NET MVC site where I plan to use Lucene.Net. I've envisioned a way to structure the usage of Lucene, but not sure whether my planned architecture is OK and efficient.

My Plan:

• On Application_Start event in Global.asax: I check for the existence of the index on the file system - if it doesn't exist, I create it and fill it with documents extracted it from the database.
• When new content is submitted: I create an IndexWriter, fill up a document, write to the index, and finally dispose of the IndexWriter. IndexWriters are not reused, as I can't imagine a good way to do that in an ASP.NET MVC application.
• When content is edited: I repeat the same process as when new content is submitted, except that I first delete the old content and then add the edits.
• When a user searches for content: I check HttpRuntime.Cache to see if a user has already searched for this term in the last 5 minutes - if they have, I return those results; otherwise, I create an IndexReader, build and run a query, put the results in HttpRuntime.Cache, return them to the user, and finally dispose of the IndexReader. Once again, IndexReaders aren't reused.

My Questions:

• Is that a good structure - how can I improve it?
• Are there any performance/efficiency problems I should be aware of?
• Also, is not reusing the IndexReaders and IndexWriters a huge code smell?