Help with a Word macro that capitalizes the first letter of a word

I need a bit of code for a Word macro that will capitalize the first letter of a word if it's not already capitalized.  But if it is already capitalized, then I don't want it changed.

My current macro uses Shift-F3, which is Word's toggle between cap/not cap.  It works great when the target word is lower case, but if the word is already capped, it lower cases it, which is not what I want.

So, here's the situation in which I would use it.  Say there's a run-on sentence like this:

Mary likes apples Tom likes oranges.

I want to put my cursor after the s in apples and run the macro.  The macro should type a period, move over one space, add a second space, select the T in Tom, and capitalize it if it's not capitalized and leave it alone if it is capitalized.  Then I want the cursor to end up just to the left of the T in Tom.  

And here's my current code:

Sub insertaperiod()
'
' insertaperiod Macro
'
'
    Selection.MoveLeft Unit:=wdCharacter, Count:=1
    Selection.MoveRight Unit:=wdWord, Count:=1
    Selection.MoveRight Unit:=wdCharacter, Count:=1, Extend:=wdExtend
    Selection.Range.Case = wdNextCase
    Selection.MoveLeft Unit:=wdCharacter, Count:=2
    Selection.TypeText Text:="."
    Selection.MoveRight Unit:=wdCharacter, Count:=1
    Selection.TypeText Text:=" "
End Sub

Thank you to this very helpful group!