<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
<xsl:output method="xml" indent="no" />
<xsl:template match="p/text()[substring(., 1, 1) = ' '][preceding-sibling::node()[1][self::sub]]">
<s />
<xsl:value-of select="replace(., '^s+', '')" />
</xsl:template>
<xsl:template match="@*|node()">
<xsl:copy>
<xsl:apply-templates select="@*|node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>