Wrap an entire element if it starts with text

I have a series of <entry> elements whose entire contents I want to wrap in
a <p> element.

For example, here is before:

<entry>This is a raw entry that needs a p element.</entry>

Here is after:

<entry><p>This is a raw entry that needs a p element.</p></entry>

I want to ignore <entry> elements that already have a top-level child, like
this:

<entry><note>I don't want to add p to these.</note><entry>

I also want to ignore <entry> elements that just consist of a space, like
this:

<entry> </entry>

With my stylesheet and XPath statement below, everything works fine.
However, it doesn't handle elements like these, that also need to have their
contents wrapped:

<entry>This contains a nested <note>child</note> and I need these wrapped as
well.</entry>

I want to get this:

<entry><p>This contains a nested <note>child</note> and I need these wrapped
as well.</p></entry>

Any pointers or suggestions would be appreciated. Thank you very much.

Rick

<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl='http://www.w3.org/1999/XSL/Transform'
version='1.0'>
  <xsl:template match="node() | @*">
    <xsl:copy>
       <xsl:apply-templates select="@* | node()"/>
    </xsl:copy>
  </xsl:template>
  <xsl:template match="//node()[parent::entry[not(*)][.!=' ']]">
    <xsl:element name="p">
      <xsl:copy>
         <xsl:apply-templates select="@* | node()"/>
      </xsl:copy>
    </xsl:element>
  </xsl:template>
</xsl:stylesheet>