Post title manipulation

To make few themes identical to original designs I am trying to make this function work properly:

<?php
function pcom_title($title) {
    $title = explode(" ", $title);
    $return_title = '<span class="blue">';
    for ($i = 0; $i <= sizeof($title); $i++) {
        if ($i == 1) {
            $return_title .= $title[$i] . '</span>';
        } else {
            $return_title .= $title[$i] . ' ';
        }
    }
}
?>

Funny that it works if I manually pass value to it, but when I try to call this function from my theme following way it fails:

<?php
pcom_title(bloginfo('name'));
?>

It just prints out 1 line with no modifications. It seems as it was some kind of text that is impossible to split.

Anyone could suggest anything?