Delete carriage return

I want to delete the carriage return if the word I'm searching is alone on the line.
I'm doing that this way :
(wpDoc is a TWPRichText)

wpDoc->Finder->ToEnd();

while(wpDoc->Finder->Prev(sWord))
{           
   wpDoc->CPPosition = wpDoc->Finder->FoundPosition;
   wpDoc->SelectLine();
   sLine = wpDoc->SelText;

   if(isAlone(sLine, iLength))
   {
      wpDoc->SelectLine();
      wpDoc->SetSelPosLen(wpDoc->SelStart + wpDoc->SelLength, 1, false);
      wpDoc->ClearSelection(true);             
   }
}

I use a button to launch the function.

The function works perfectly when I click on the button immediately after loading the RTF File in the editor, but when I click on the TWPRichText before launching the function, it deletes more text than needed.

Do I use the right way to do what I want to do? Is there any better solution?
Why doesn't the function work every time I try it?

I need help please.
Thanks.

It works fine with:

par := WPRichText1.FirstPar;
while(par<>nil) do
  begin
     if par.ANSIText= 'test' then
        par := par.DeleteParagraphEnd;
        par := par.NextPar;
     else par := par.NextPar;
  end;
WPRichText1.ReformatAll(false, true);

Thanks!