changing your negative text-indent to negative margin seems to yield the desired results:
Code:
span.drop {
font-size: 300%;
line-height: 1;
font-weight: bold;
margin-top: -0.1em;
margin-bottom: -0.1em;
float:left;
}
div.poetry {
text-align: left;
margin: 1em 0 1em 2em;
}
div.poetry div.line {
margin: 0;
padding-left: 3em;
margin-left: -3em;
}