Put Frequent File I/O Operations Within A SyncLock Block?

Say I have some code that does this:

Public Function AppendToLogFile(ByVal s As String) As Boolean
Dim success As Boolean = True
Dim fs As IO.FileStream = Nothing

[Code].....

First of all: is it a problem that I have that Try/Catch/Finally block inside of a SyncLock?

Second of all: suppose this code runs, on an event, potentially many times within a small timeframe--say, ten times in one second. Is it OK to have it SyncLock like this, or would it make more sense to have it add a line to a Queue, and then write all the lines from the Queue to the file on a timer that goes off, say, every second?