adding where clauses to linq query

I've found examples of how to "dynamically" add more where clauses to a linq query, but I'm not sure how to make it work with my specific query.

Here's one example, and here's another. Now here's a look at the query that I have:

var result = (from EventLogEntry elog in el.Entries
              where (elog.InstanceId == 4107)
              orderby elog.TimeGenerated descending
              select elog).ToList();

var query = from EventLogEntry elog in el.Entries
            orderby elog.TimeGenerated descending
            select elog;

The first example shows the hard-coded InstanceID == 4107, but I want to be able to add in more where clauses. All of the examples I've seen say to do:

query = query.Where(el.Entries => el.Entries.Message.Contains("error"));

or something like that. But my query is setting defining "the source" as an EventLogEntry object, so when I try and extend the where clause, it doesn't recognize the fields that I want to do my where on....

Any help with this?

This is what I tried to add, and intellisense doesn't recognize any of it:

if (!String.IsNullOrEmpty(sc.Message))
    query = query.Where(elog.Message.Contains(sc.Message));

Updated (this is the working version):

var query = from EventLogEntry elog in el.Entries select elog;

try
{
    if (!String.IsNullOrEmpty(sc.Message))
        query = query.Where(elog => elog.Message.Contains(sc.Message));

    query = query.OrderBy(elog => elog.TimeGenerated);

    var result = query.ToList();
}
catch
{
    throw;
}