The favored order (not so evident in the lines you quote from Prop.4.4, but cf. e.g. the first four couplets of the poem) is adjective-noun, setting the scene before resolving it later in the line or at line end. That’s quite regular in Latin verse. Rhyming is secondary to syntactical agreement.
This pattern in the pentameter of elegiacs was a mannerism of some Hellenistic poets. An extreme example is this poem by Hermesianax (early 3rd cent. BCE):
Οἵην μὲν φίλος υἱὸς ἀνήγαγεν Οἰάγροιο
Ἀργιόπην Θρῇσσαν στειλάμενος κιθάρην
Ἁιδόθεν· ἔπλευσεν δὲ κακὸν καὶ ἀπειθέα χῶρον,
ἔνθα Χάρων κοινὴν ἕλκεται εἰς ἄκατον
ψυχὰς οἰχομένων, λίμνῃ δ’ ἐπὶ μακρὸν ἀϋτεῖ (5)
ῥεῦμα διὲκ μεγάλων ῥυομένῃ δονάκων.
Ἀλλ’ ἔτλη παρὰ κῦμα μονόζωστος κιθαρίζων
Ὀρφεύς, παντοίους δ’ ἐξανέπεισε θεούς,
Κωκυτόν τ’ ἀθέμιστον ὑπ’ ὀφρύσι μειδήσαντα·
ἠδὲ καὶ αἰνοτάτου βλέμμ’ ὑπέμεινε κυνός, (10)
ἐν πυρὶ μὲν φωνὴν τεθοωμένου, ἐν πυρὶ δ’ ὄμμα
σκληρόν, τριστοίχοις δεῖμα φέρον κεφαλαῖς.
Ἔνθεν ἀοιδιάων μεγάλους ἀνέπεισεν ἄνακτας
Ἀργιόπην μαλακοῦ πνεῦμα λαβεῖν βιότου.
Here every single one of the pentameters has an adjective at the mid-line caesura and its noun at line end. They don’t necessarily have to rhyme, it’s more a matter of the syntactical patterning.
Augustan poets found the arrangement aesthetically appealing and emulated it, but less monotonously.
Ovid has a nice little catalogue of contemporary women’s hairstyles in elegiacs (Ars Amatoria 3.135ff.):
longa probat facies capitis discrimina puri:
sic erat ornatis Laodamia comis. …
alterius crines umero iactentur utroque: (hex.)
talis es assumpta, Phoebe canore, lyra. (pent.)
altera succinctae religetur more Dianae,
ut solet, attonitas cum petit illa feras.
huic decet inflatos laxe iacuisse capillos,
illa est astrictis impedienda comis.
As if to say I can go on like this ad infinitum.
The so-called “golden” form of the hexameter is comparable: adj.1 adj.2 verb noun1 noun2, e.g. Prop.4.1.15 nec sinuosa cavo pendebant vela theatro (followed by pent. pulpita sollemnis non oluere crocos). Catullus started the fashion (e.g. 64.59 irrita ventosae linquens promissa procellae, of Theseus deserting Ariadne on the shore of Naxos), and the Augustan poets embraced it, Virgil among them but taking care not to overdo it. “Golden” or not, the adjectives regularly precede the nouns, which complete the picture. (E.g. Ars Am. 3.395 spectentur tepido maculosae sanguine harenae, of the gladiatorial arena as a good place for women to find men.)
A good book is L.P. Wilkinson’s Golden Latin Artistry.