Horace is difficult. Extreme hyperbaton and radical compression are his trademarks. And I think he deliberately tries to surprise or even mislead the reader by scrambling the word order in unexpected ways, so that the idea of a sentence unfolds gradually, not all at once. There's a certain sense of satisfaction or pleasure like the unexpected resolution of a dissonance in music, as the syntax falls into place and the meaning becomes evident.
Sometimes you just have to resort to "decoding" by the hated "grammar-translation" method. Eventually, it becomes easier to pick up the syntax without having to think about it.
It helps to first figure out the subject and the main verb. Here, in the first clause,
prensus can only be nominative singular, so that must be the subject (in any case, you wouldn't expect
otium to ask for something--
otium is something someone asks for--and
diuuos must be accusative plural, so it can't be the subject), and
rogat is the verb.
in patenti should alert you to look for a noun modified by
patenti, and you have it in
Aegaeo. If you look up
rogo in Lewis and Short,
http://perseus.uchicago.edu/cgi-bin/phi ... isandshort
you'll see that it can take a double accusative, meaning "to ask someone for something":
II Transf., to ask, beg, request, solicit one for a thing (so predominantly in the class. per.; syn.: posco, oro, obsecro, ambio, capto); constr. aliquem (rarely ab aliquo) aliquid, aliquem, aliquid, with ut, ne, or absol.
atra nubes condidit -- you need a noun to agree with
atra and a subject for
condidit; here only
nubes can fill those functions. Look up
nub- in a dictionary that isn't on-line, so that you can find words that begin with
nub-, and you'll see that
nubes is nominative singular.
This can be a tedious and time-consuming process at first, but as you read more, you'll start to see the syntax of new material without having to resort to "decoding".
By the way, you should definitely try to read this metrically. These Sapphic stanzas are easier than hexameter, I think, because the meter doesn't allow substitutions of two shorts for a long--the verses are isosyllabic--and the rhythm is ingratiating.