Using PHP to Convert HTML to UTF-8 for PDF output

I am working with a PHP class called mPDF, which is a PHP class that generates PDF files from UTF-8 encoded HTML.  It works great, but everything going into it MUST be UTF-8, which is the thing tripping me up I think!

So here is some quick test code that works:

1      <?php
2      define('_MPDF_PATH','mpdf/');
3      include("mpdf/mpdf.php");
4
4      //this is 6x9 book format
6      $mpdf=new mPDF('en-US','Royal','11','dejavuserifcondensed',32,25,27,25,16,13 );
7
8      include "poemfile1.php";
9      $mpdf->WriteHTML($html);
10      $mpdf->Output('mpdfA.pdf','I');
11      exit;
12      ?>

poemfile1.php looks like this:
<?php
$html='
<h1>Title</h1>
<pre>
lots of text</pre>';
<?php>

Using textpad I had to save poemfile1.php AS UTF-8 format. Then when I run the script, my pdf comes out just fine.

Now, what I really want is to write to a file called 'selections.txt' which will contain one or more poems selected by the user and which come from mySQL database.  At this point I haven't brought the db into the picture yet.  Right now, I just want to create the selections.txt file, write to it one or more poems, and then create my pdf.  If I can get *that* to work, I'll move on to selecting from the DB!

So after googling and reading tons of stuff about PHP and UTF-8, I am now totally boggled.  Here is the test code I am trying in the attempt to CREATE a file and save it as UTF-8 format:

1      <?php
2      //iconv_set_encoding("output_encoding", "UTF-8");
3      //iconv_set_encoding("input_encoding", "UTF-8");
4      //var_dump(iconv_get_encoding('all'));
5      //==============================================================
6      define('_MPDF_PATH','mpdf/');
7      include("mpdf/mpdf.php");
8      $selections_file="selections.txt";
9      $input_file="cartog3.htm";
10      //$file_array= array("cartog3.htm","prowl3.htm");
11
12      //this is 6x9 book format
13      $mpdf=new mPDF('en-US','Royal','11','dejavuserifcondensed',32,25,27,25,16,13 );
14
15      $input=file_get_contents($input_file);
16      //echo $input;
17      $fh=fopen($selections_file,"w") or die("can't open file");
18
19      //foreach ($file_array as $poetry_file) {
20            //fwrite($fh,utf8_encode($input));
21            fwrite($fh,iconv("ISO-8859-1", "UTF-8", $input));
23            fclose($fh);
24            //file_put_contents($selections_file, $input, FILE_TEXT|FILE_APPEND);
25      //}
26
27      $fh=fopen($selections_file,"r") or die("can't open file");
28      $html=fread($fh, filesize($selections_file));
29      fclose($fh);
30      echo $html;
31
32      $mpdf->WriteHTML($html,2);
33      $mpdf->Output('mpdfA.pdf','I');
34      exit;
35      ?>

You can see from various commented lines different things I've been trying.  I have saved the file cartog3.htm as a UTF-8 file and it now contains ONLY html and text (unlike the version that works that includes a PHP file with PHP information in it).  However, when I echo $html (on line 30), my text is preceded by the characters:  

And the PDF of course is just a bunch of junk characters.

Can anybody help?  I get the feeling that I am somehow making it harder than it needs to be?

Thanks!