Hi Justine,
While you are waiting for sir Joe's reply, allow me to answer this structure of the language that
perplexes your mind.
As we all know most English sentences follow the order in which the subject precedes the verb
which can be represented structurally as:
Normal Word Order: S – V – O
The case you presented is one of the so many exceptions of the language.
So, let's analyze the examples you lifted from your source.
Example Sentences:
1. "Little did Senator De Lima realize that trying to appease and reason with news hounds would sink
her deeper and deeper into the pit.”
2. "Not only did I want to look at them, I wanted to act like them."
3. “Should you need any further information, please do not hesitate to contact me.”
Unlike the traditional rule wherein the subject comes before the verb and its complement, some
situations call for the inversion of word order and the above examples follow the rule of inversion.
Inversion operates in the first and second sentences. These sentences obey the rule that if a
negative word/expression such as rarely, scarcely, never, hardly, and little begins a sentence, then
the verb, should precede the subject. The same goes true for the conditional statement as in the case
of sentence number 3.
And to answer your question if the structure is a matter of stylistic usage, my answer is not at all
times. Please see the case below:
At the park he plays.
The above example is in its inverted order. Inverted for stylistic purposes.
He plays at the park.
But not,
Wrong: "Little Senator De Lima DID realize that trying to appease and reason with news hounds
would sink her deeper and deeper into the pit.”
There are some other cases aside from these that call for inversion. I'll leave the comprehensive
discussion to sir Joe.
Hope this explanation helps you.