Blonde moment...

Before I try and do it a harder way, can anybody remind me how to get
the desired from the following? I simply want to split
"aTypicalCamelCasePropertyName" into a "a Typical Camel Case Property
Name" (fully expanding upper-case blocks as the simplest answer to the
ambiguity)

Console.WriteLine(Regex.Replace(
           @"testInputOfWhatIWantUPPERS",
           @"([a-zA-Z])([A-Z])",
           @"$1 $2"));

I want: "test Input Of What I Want U P P E R S"
I currently get: "test Input Of What IWant UP PE RS" - i.e. the upper-
case is getting consumed each time.

Any offers?

Marc