For the most part, there is no a place for omniscience and objectivity in To the Lighthouse. To understand why, we need to go back in time about a decade to see Woolf's frustrations with the conventional novel, and with how women were depicted in novels. As she was writing her last conventional novel Night and Day, she was feeling increasingly frustrated with its conventional form, which seemed to her not to capture how life is really lived. While she was revising that novel, during a rest cure, she wrote a short story that she later described as a breakthrough to her modernist, stream-of-consciousness method. She called it "An Unwritten Novel," and it is about the story a female passenger on a train weaves about another passenger. The first character concocts an entire elaborate tale about the other woman's travels. Then leaving the train, the first character watches the woman greet her husband and son and realizes the story she had concocted was completely wrong.
From this, Woolf understood she could convey what she believed what was more realistic than omniscient narration or the illusion of objectivity (which implies getting the facts completely straight, ie, telling the "truth"). She could, instead, convey people's subjective (opinionated, colored, flawed) thoughts as they have them. This is how life is lived: none of us truly know who another person is, as Lily Briscoe ruminates, none of us are God, none of know, really, the whole truth of life. We can't, as men had done for thousands of years, pronounce in a knowing and godlike way what women think or why they behave as they do, because men don't really know. Woolf had long been frustrated at male mischaracterizations of women in literature and through her new method thought she could get at what women are more accurately.
As a result, the novel is told through the thoughts of various people in it, including characters who would traditionally be overlooked, such as Mrs. Ramsey, little James, and Lily. These thoughts don't claim omniscience or objectivity—they simply reflect the way people live through a veil of subjectivity or personal opinion.
The one exception to this lack of omniscience is the novel's short central section, in which ten years are described passing and which is essentially narrated for the perspective of the house, which has an omniscient perspective over the events of this section. Yet even here, the narration still isn't objective. Instead, Woolf trying to communicate something that obsessed her: that we don't experience the flow of time objectively. As the novel shows, one day can feel like ten years, while ten years can flash by in an instant.
We read Woolf today not only because she wrote beautiful prose, though she did, but because she was trying to more fully capture the way people really experience life.